Automatic thread-cutting tool



April 15, 1930. I P. o. HECHT v ,9

AUTOMATIC THREAD CUTTING TOOL Filed June 4, 1925 3 Sheets-Sheet 1 PAUL 0 HEGHT INVENTOR.

A-TTORNE Y.

24 II II I III II 24 ||l I ll I l I I I I I I I I I II I I I I I I I I l i III /9 I ii I w 4% /4 IM 20 4 April 15, 1930.

AUTOMATIC THREAD CUTTING TOOL Filed June 4, 1925 3 Sheets-Sheet 2 FIE-'3 F IINVENTOR.

F WM;

A TTORNE Y.

,April 15, 1930. P. o. HECHT 1,754,949

AUTOMATIC THREAD CUTTING TOOL Fi ed June 4, 1925 3 Sheets-Sheet 3 P/IUL 0 HEGHT INVEN TOR.

A TTORNE Y.

Patented Apr. 15, 1930 UNITED STATES? PATENT OFFICE PAUL 0. nnon'r, 0F DAVENPORT, IOWA, ASSIGNOR TO B & n MFG. oo., or ROCK ISLAND,

rumors, A CORPORATION OF ILLINOIS AUTOMATIC THREAD-CUTTING TOOL Application filed June 1,

My invention relates to means for interiorly or exteriorly threading articles, such as rods, pipes, nuts, and the like and more particularly to mechanisms of this character adapted to operate automatically, to thread such devices and remove the threading means therefrom without reversing the direction of rotation. Y

Among the objects ofmy invention are to producea superior automatic thread cutting tool; to produce a device of the character stated which will cut threads to a definite predetermined point and then be released for withdrawal. from the article being threaded,

i to. provide an improved locking and tripping mechanism for an automatic device of the character described; to. provide improved holding and guiding means having movable thread cutting elements;.'to provide means for moving the thread cutting elements away from the work in such a direction that there will be no scoring or damaging of thethread faces by the withdrawing cutting members; and such further objects, advantages and capabilities as will hereafter morefully appear ferred embodiment ofthis invention; Fig. 2

is a bottom plan view of the structure shown in Fig. 1 with part ofthe elements omitted; Fig. 3 is a broken longitudinal sectional elevation of this device with the tripping mechanism omitted. therefrom; Fig. 4 is a trans verse section substantially along the plane indicated by the line 4-4 Fig. 3; Fig. 5 is 1925. SeriaLNo. 34,833.

a broken longitudinal section substantially. along the broken plane indicated by the line 55 Fig. 6; Fig. 6 is a bottom plan'view of the structure shown in Fig. 5, the same being similar to Fig. 2 but with the tripping ring omitted; Fig. 7 is a bottom plan view of the chaser holding and guiding block; Fig. 8 is a lateral viewof the structure shown in Fig. 7; Fig. 9 is a face View at a right angle to the view shown in Fig. 8 Fig. 10 is a bottom plan view of the holding means for holding the thread cutting elements or chasers in the guiding or chaser carrying blocks; Fig. 11 is alateral face View of thestructure shown in Fig. 10; Fig. 12 is a lateral view at a right angleto Fig. 11; Fig. 13 is an ele- V2tl31011. of one of the thread cutting elements or chasers; Fig. 14 is a plan view thereof;

and Fig. 15 is a transverse section through the flange 19 and'joint 21. y

Referring more in detail to the annexed drawings, numeral 1 designates the shank of my improved tap or die head whereby this device is attached to the machine with which it is used for cutting threads. This shank is provided with a flange 2 which forms a holding means for the blocks 3 which reciprocate laterally to carry the thread cutting elements 4 to open and closed position. In the construction shown, these thread cutting elements are provided with shoulders 5 and 6 which engage respectively with. shoulders 7 and 8 of the guiding blocks 3. The holding blocks 9 are threaded with threads of the same pitch as the thread cutting elements and engage the threads thereof to hold these elements in properly adjusted positions. Screws 10 are passed through the blocks 9 into the guiding blocks 3 and hold all these parts properly assembled. Screws 11 abut the outer ends of the blocks andhold the shoulders 5 and 6 tightly engaged with the shoulders 7 and 8, when the screws 11, are turned in to force the blocks 9 against the cutting elements. In forming the thread cutting members 4, cylindrical bars are threaded throughout their lengths and then they are divided into two or more parts, longitudinally. From these threaded parts are ormed the thread cutters.

In making the holding members 9, a ring of proper thickness and diameter is threaded interiorly and then out along non-radial planes parallel to the axis of the ring, the planes occurring in pairs arranged in parallelism and at a suitable distance from each other so that the blocks 9 will be of the proper width when smoothed and polished. The books should be equally spaced around the ring so that, when mounted in the openings in blocks 3, the threads will occupy the same relative positions that they had in the ring.

Furthermore, by reason of the method of forming the blocks or holding members 9 all cutters 4 are interchangeable. The blocks 9 must be numbered consecutively as they occur in the ring and be used in the same order when mounted in the tool as shown in Fi 6. From this it results that the threa s of the cutters always line up perfectly, thus causing the cutting of perfect threads. The threads of the thread cutting elements 4 and the blocks 9 are so cut that the threads of the cutters always match properly and do not misfit in the cutting operation.

The shank 1 is hollowed out as indicated at 12 for the reception of the thread cutting elements 4. As will readily be appreciated, these are adjustable so that, in event they become broken oil at or below the lower end of the head, they can be adjusted to the desired position, merely by loosening the proper screw 11 and removing the corresponding screw 10, thus permitting removal of the block 9.

Surrounding the shank 1 is a ring 13 provided with an outwardly extending flange 14 which is perforated for the passage of springs 15 resting at their upper ends against the ring 16 and at their lower ends being seated in sockets 17 in the flange 2. Assuming the flange 2 to be held stationary the springs 15 have a tendency to push the plate 16 upwardly against the lower end of the ring 18. This has a screw threaded engagement at 18 with the internal flange 19 of the shell 20. Therefore, when the shell is free to move. the springs 15 will cause the same to be moved upwardly relatively to the shank 1, resulting in an operation which will presently be described.

The upper end of ring 13 preferably has an overlapping connection as shown at 21 with a ring 22 surrounding the shank 1, as shown most clearly in Figs. 1 and 5. The rin 22 is preferably made of hardened steel an is beveled at its upper end as shown at 23 to serve as a cam for actuating the dogs 24,

the latter serving as means for holding the shell 20 downwardly in its normal operating position. The dogs 24 are provided with shoulders 25 for engaging the upper edge of a ring 26 which is secured to the upper end of ring 18 by the screws 28, passing through ring 27 and into flange 29 at the upper end of ring 18. A ring 30 is secured by any desired means such as a pin 31 to the shank 1 and serves as an abutment for the upper edges of the dogs 24, as shown clearly in Fig. 1. These dogs are pressed outwardly by the spring 32 which is mounted between them in the same slot in which the dogs 24 slide in the shank 1. From this it will be seen that when the shell 20 is forced downwardly, carrying with it rings 18, 26 and 27, the spring 32 will cause the dogs 24 to move outwardly until the shoulders 25 engage above the top of ring 26 thereby locking the shell and its connected parts in lowered position. The ring 18 may be adjusted longitudinally in respect to shell 20 by loosening the set screws 33 and then turning the ring relatively to the shell. Any such adjustment will cause the dogs 24 to engage fresh portions of ring 26, thus obviating undue wear at any one point.

As shown in Figs. 1 and 2 a tripping ring 34 is carried at the lower end of this mechanism by a plurality of posts 35 which extend upwardly through holes 36 in the flange 2 and into holes in the flange 14 of ring 13. This flange is provided with holes in which are mounted set screws 37 which are used to lock the posts 35 in adjusted position. The set screws 37 are provided with sockets 38 for the application of a screwdriver or other means for turning the set screws into place. Access to these set screws is gained by means of openings 39 in the shell 20. Attention is called to the fact that the tripping of the dogs 24 may be caused by engagement of any part of the lower face of ring 34 with the work or work holder, but that it is necessary for the ring to be pressed upwardly relatively to the thread cutters until the dogs are released from ring 26. The shell 20 is pressed downwardly and the springs 15 compressed by engagement of ring 27 with a part of the machine by which this tool is carried and operated. In a broad sense the shell 20 includes the outer sleeve, the ring 18 adjustably mounted therein, and the rings 26 and 27 secured to the latter by means of the screws 28. Though this shell includes several elements, it is functionally one element because the parts are secured together for simultaneous operation and to produce a single result.

In the edges of the flanges 2 and 14 are aligned notches forming slideways for the cam-carrying keys 40. These are secured to the flange 19 of the shell 20 by means of screws 41 passing through the flange and into the ends of the keys 40. This construction makes these keys, during operation, essenti a'lly al part of the SlIBHL QO and: causes them to move witlr the shells.duringsucli:operation.

The keys are laterally notche d as shown atAQ and each onecarries on the-face ofthisuiotchwhich cooperates with a cam. groove i tin one lateralface oftheblockii. Thereparticularly desirable with adie.

When the set screws 33 are loosened and sleeve 18 turned with respect-to: the shell, it

results in the shell being adjusted longitudinal ly,.rclatively to'the shankl. This adjusts the keys 40, blocked and thread cutters &. It is by this means thatthethread cutters are adjusted to thread-diiierent sizedopenings, the amount of adjustment varying as much a eof aninchor more.

Thelower iiace of the flange 2 isprovided with ,notches which serve as guides for the blocks or chaser carrierseh The-blocks are beveledv at 46 to correspond to the upward bevel. inthc notches lfil Notches l7 inthe shell 20' correspondin size and 'location with the notches 45 and permit the blocks 3' to move outwardly inthe shell. Keys 48 are rigidly mounted in grooves cut in alateral walltoffi notchestd and cooperate with i grooves l9 in blocks 3- to-hold these blocks from falling' out otzthe tap head. The notches 49! are parallel. with the edges 460i the blocks so that the latter can. slide freely with. respect toxboth thelu pper tacos of lilltIlOllCllfiSdt) and the-keys48... Due to the relative angularity of thesetguides. and the inclined faces of the screwthreads, the threads ofthe thread cut: ters i willbe: carried away. from. the completed threads at. such an. angle that there will he no scoring. of the faces of those threads nor any breaking thereof by the withdrawing cutting, members,

Operation In use, the shank 1 of this device is applied toand secured in an appropriate rotating spindle and, theparts are so ad usted i that thetrilpping ring 34: will engage the work-or a. fixed 1 stop and push the ring 22 upwardly far enough tomove the dogs 24in until ring 2% and withit ring 18 and shell 20 are 1 released for upward movement under the influence ofspringsilti pressing; againstthe plate orring 16 W'hen theshell. 20 is released for upward imovementit carries with itthe keys m carrying cams 413... These move vertically and thereby, force-.the-blocks 3inwardly. by

reasonof theicamaction. These blocks 3 are alsb given upward direction by reason of the CO-EtGlDlOIlr. of the keys 48 and slots 4-.9, Since the slots 49 are parallel with the-inclined faces of the notches 45, the blocks; 3. will. slide in this direction. The angle: of inclination of the direction. of motion otthe blocks. is such that: the threads of the. cutting elements are moved away from the elements being threaded at such an angle that there will be no scoring or breaking of thethreads. If the cutting end of one ofithe cutting eles ments 4 should bebroken oil for any: reason, it isnot necessary to throw away-the entire die or tap but the broken cutting. element; may be moved outwardly sothat itwill extend downwardly to substantially the same plane as the lower ends of the other. elements; By reason of the fact that these cutting ele ments extend upwardly for a considerable. distance into the opening 12, it will be possible to make several such adjustments before oneof the cutting elements is entirely used up.

Bypreason of the -fact that the: tripping mechanism operates so nearly absolutely the same placeeach time and the further factthat it is'possible to make such minute adjustment of the parts to secure tripping of thermechanism and release ofthethread cutting ele ments from the threads just cut, it is possible to out a thread entirely into the inner face of a: cap nut or the like orto the shoulder of a bolt, where the head and body of the: bolt join. Also, owing to the facththat a plu-' F rality ofdogs: 24: are used in holding the shell downwardly, there is no tendency towardhi'ndin-g of the shank 1; and the shell when the. latter is released formovementz.

From the foregoing it be seen that I have provided a novel device whereby the various objects set forth abovev may be accomplished. andfthat thedevice is entirely automatic and accurate, in its operation.

It will of course: be; understood that the specific description of structure set; forth above may bedepartcdfrom without depart ingfrom the spirit, of my invention...

Having now described my invention, 1 claim:

1. In mechanism of the character de scribed, body comprising a shank and a flange, a shell surrounding the. body and sliding on the flange, said shell having at its upper end. a ring shaped abutment, locking dogs carried by the shank and. engagingthe said abutment to lock the shell in lowered position, and a ring slidable between the shank and shell and, in one position, engaging and Withdrawing the dogs from looking position.

2. In mechanism of the character described, a body comprising ashank and a flange, a shell surrounding the. body and sliding on the flange, said shell having; at its upper end a ring shaped abutment, locking dogs carried by the shank and engaging the said abutment to lock the shell in lowered position, springs within the shell and tending to separate the shell and flange by moving them longitudinally relatively to each other, a ring slidable between the shank and shell and, in one position, engaging and withdrawing the dogs from locking position, and a continuous abutment below said shell and connected to the slidable ring to actuate the same to release the dogs and permit relative movement of the body and shell.

3. In a thread cutting tool, a supporting ;member carryin a plurality of supports for thread cutters, t read cutters carried by the supports and adjustable with relation thereto, said supports having guiding grooves and actuating grooves, a shell laterally surround- .ing the aforesaid structure and carrying actuating keys, said keys cooperating with said actuating grooves for actuating the said supports to move them in radial planes toward and from each other, and means for holding the thread cutters and releasing dogs,

:thread cutters,

them for adjustment.

4. In an implement of the character described, a body member, a shell surrounding and slidable longitudinally of the body member, a ring within the shell and slidable between the shell and body member, pins mounted in and slidable longitudinally of the body member, a substantially circular actuating member beyond the lower end of ithe shell connected to the pins and, when actuated, pushing the pins inwardly, said pins being connected to the ring and serving to move the same longitudinally when the actuating member is moved longitudinally of the implement.

5. In a structure of the character described, a body member having a shank, provided with laterallydirected holes, locking do movable longitudinally in said holes and transversel of the shank, a shell movable longitudina ly of the shank and engaged by the dogs, means for moving the shell longitudinally of the shank in one direction, means slidable on the shank to engage the and work engaging means connected to the last means to move the same and force the dogs to recede into the holes in the shank.

6. In a thread cutting tool, a supporting member carrying a plurality of supports for thread cutters carried by the supports, said supports having guide grooves and actuating grooves, a shell laterally surrounding the aforesaid structure and carrying actuating keys, said keys cooperating with said actuating grooves for actuating the said supports to move them in radial planes toward and from each other and means for adjusting the diameter of the thread cutting tool so as to regulate the diameter of the completed thread.

7 A tool of the character described having a shank, hollowed out at its forward end to form a receptacle for thread cutting elements, said shank having notches extending radially from the hollow, carriers in said notches carrying longitudinally adjustable thread cutting elements, guiding means to guide the carriers, and adjusting means for adjusting the positions of the carriers to vary the positions of the thread cutting elements.

8. In a tool of the character described, a body member, a sleeve reciprocating longitudinally thereof, a shell adjustably connected to the sleeve, thread cutting elements carried by the body member and movable diagonally in radial planes thereof, said thread-cutting elements being longitudinally adjustable, connections between the shell and thread cutting elements whereby axial movement of the former causes radial movement of the latter and means preventing or permitting relative adjustment of the sleeve and shell whereby the diameter of threads cut may be varied.

9. In a tool of the character described, a body member having a plurality of holding and actuating notches in an end thereof, guiding means within the notches arranged at an acute angle to the axis of the tool, chaser carriers mounted in the notches and guided thereby along substantially radial planes of the body member, said guiding means causing the chasers to move at an acute angle to the axis of the body member when moved along the said planes.

10. In a tool of the character described, a plurality of thread-cutting members, movable radially toward and from each other and diagonally of the axis of the tool, laterally movable carrying members holding and guiding the thread-cutting members in their movements toward and from each other and to which the thread-cutting members are adjustably secured, a shell movable longitudinally in one direction to actuate the carrying members in a direction transversely of the longitudinal dimension of the tool, resilient means to move the shell in the opposite direction, locking means to hold the shell in one actuated position, and tripping means movable longitudinally of the tool for releasing the locking means to permit the shell to move under the influence of the resilient means.

11. In a thread-cutting tool, a supporting member carrying a plurality of supports for thread cutters, thread cutters carried by the supports, said supports having grooves whereby they are guided diagonally of the supporting member and grooves whereby they are actuated to move in planes substantially radially of said member, a shell laterally surrounding the aforesaid structure and carrying actuating keys, said keys cooperating with said actuating grooves for actuating the said supports to move them in radial planes toward and from each other. H 

